Stabilized chlorinated solvents and method of stabilizing such solvents



.gOiFFiCE STABILIZED CEORINATED SOLVENTB AND METHOD OF ST G SUCH 80L- VENTS m r. Dinley; Detroit, mto James H. Bell, Psdeiphla, Ea.

No Drawing. Application y 15, i934,

Serial No. teases 10 Glalms. h7

My invention relates to volatile chlorinated solposure of the (hot) solvent to the atmosp r vents and their purification, stabilization, and inthe partly open apparatus resultsindecomposiuse. Such solvents are exemplified by triehlor tionyielding available chlorine and/or acid, by methane, tetrachloromethane, dichlorethane. tetaction of the solvent with the atmospheric 5 rachiorethane, trlchlorethylene, and tetrachlormoisture, and with water that finds it way into 5 ethylene. An object of the invention is to prethe aptus. vent corrosion or other such action on metals I have furtherfound that in Practi e such exposed to such solvents,even when the soltroubles can be overcome by prepa the sviveht vents are heated and vaporized, and are exposed or carrying out the treatment with it in suitable 10 to the air or otherwise in contact with moisture. W y -P y both. One way of doin this 10 Such corrosion may/ arise in the cleaning of is to carryout the treatment with. the solvent metal parts with chlorinated solvents, and in in the presence of a reagent that will neutralize the use of such substances in metallic apparaor eliminate the available acid and chlorine, such. tun-for cleaning or for other purposes. The as an alkali or an alkiline metal or compound use of such solvents as cleaning and degreasing that is readily chlorinatable,-and preferably 15 agents has been widely attempted, sinc they ar water-insoluble or nearly so. Water soluble alwell hown as solvents for oil and other grease. kalis have the general drawback that any excess This application is a divisional continuation-inalkali may prove as'detrimental as the acid that part of my copending application Serial No. 566,- is to be neutralized. Because of their cheapness,

176, filed September 30, 1931. various forms of calcium carbonate are commer- 20 In the cleaning processes just referred to, me= cially pref Such as broken 1' r h d limetallic or other objects to be cleaned are introstone or marble. However, many other subduced into a vessel or apparatus containing the stances are blown to chemists as having suitable heated solvent and its vapor, and constantly or p op es. including a e a th and other 'i intermittently open (or partly so) to permit the metal oxides and carbonates, such as magnesium v easy introduction and withdrawal of the oboxide or carbonate, cadmium oxide, zinc oxide or jects treated. This is possible without excessive carbonate, etc. loss of solvent vapor because the latter is heavier While such substances as indicated above perthan air, and because provisions are made to conform their above-stated function of neutralizing dense the solvent vapor and prevent its escape. acid in the liquid solvent, I prefer to carry out 30 Sometimes contact or treatment with the hot liqthe treatment in the presence of an alkaloid, uid solvent is mainly relied on to clean or dewhich will stabilize the solvent or counteract the grease the object(s) or work; sometimes treatobjectionable decomposition,whether by being ment with the solvent vapor; and sometimes both. itself readily chlorinated, or by neutralizing dele- While chlorinated solvents have been found terious products formed (in the vapor). or by pre- 35 of great value for these and other purposes, their venting the usual decomposition of the solvent use has been attended with serious drawbacks. (i. e., stabilization in a stricter sense). Whatever Metal articles cleaned with such solvents are subits action, the agent employed should, of course, ject to objectionable spotting, while metallic apbe compatible with the undecomposed solvent,

4 paratus in which the solvents are used is subso as neither to react with it under the conditions 4 iect to progressive corrosion, that greatly abbreof use, nor to be driven ofi or separate from the rviates its useful life. Also, dangerous fumes are solvent. That it should not boil so much below given off, that injuriously aflect workers and the solvent as to be driven 01! by the heat is also may even render the vicinity of the apparatus implied in its compatibility with the solvent: and

uninhabitable. However, I have discovered ways such compatibility likewise implies, of course, that of obviating such drawbacks. the stabilizer dofis not decompose under the heat I have found, in the first place, that these to which the solvent is subjected in use.' A great drawbacks are not due to any action of the chlomany organic substances such as hereinafter inrinated solvents themselves, but to chlorine (presdlcated are known to chemists as having suitable 59 ent as impurity in the solvent) in available reacproperties.

tive forms, such as hydrochloric acid or other Examples of one class that appear to be eil'ecchlorine acids, and free chlorine, even. Comtive by neutralizing the (chlorine) acid, as well mercial chlorinated solvents commonly contain as by undergoing chlorination are the alkaloids, such available chlorine, and may have an acidity such as cafleine, quinine, etc. While alkaloids that is oi measurable magnitude, Moreover, exare not volatllelike some other types or stabilizers, to f and do not vaporize freely with the solvent. yetthe stabilizing or corrosion-preventing influence of their presence seems to be eifective in the solvent vapor, tending to. minimize available chlorine in the vapor, besides eliminating it from the liquid solvent.

Insofar as alkaloids are actually chlorinated by chlorine (acid) liberated by incipient decomposition of the solvent, or neutralize such acid, removal of a product of decomposition seems one probable rationale of the stabilizing eifect. This applies equally to chlorination of the stabilizer in the strict sense, involving insertion or substitution of chlorine in the stabilizer molecule, or its addition thereto, and to chlorination involving addition of chlorine acid (HCl) to the stabilizer molecule, to form a hydrochloride. In general alkaloids are chlorinated in this latter way: i. e., by forming hydrochlorides. Irrespective of any chlorination, however, it appears that alkaloids have some inhibitory power as against the usual decomposition of the solvent and/or the reaction of the resulting chlorine acid with metal. At any rate, metal treated in their effective presence (mixed with the hot liquid solvent) is protected against corrosion by contact with either the liquid solvent or its vapon-even when the latter is exposed to the atmosphere. Stabilizing influence of non-vaporizing alkaloid stabilizers felt in the solvent vapor may to a degree be due to a peculiar sort of volatilization of such stabilizers when dissolved in the boiling solvent. In general, alkaloids are soluble in (moist) chlorinated solvents, including trichlorethylene, and impart to the product an alkaline reaction when used in sufllcient proportions, such as those hereinafter indicated.

In this application, I aim to cover the alkaloid organic stabilizers, and especially the vegetable alkaloids, exemplified by cafleine and quinine.

As the alkaloids are comparatively expensive, it may be desirable to use the much less expensive solid alkalis like marble or limestone in conjunction with them, to take care of (chlorine) acid or other forms of available chlorine existing or produced in the liquid solvent. For this purpose, several handfuls of broken marble or limestone may be put into the pools of liquid in the apparatus where objects are treated with solvent, and these deposits replenished from time to time, so as to assure an ample supply at all times; and the alkaloid organic stabilizer may be added to the liquid solvent in the apparatus before it has been materially heated,-as soon as the marble or limestone has had a chance to free the solvent of its initial acid or the like. Instead, however,

of treating and stabilizing the solvent in the apparatus where objects are treated therewith, it is preferable to do this beforehand.

In general, the proportion of the alkaloid agent added to the solvent may be anywhere from about $4 of 1% to about l by weight. Such proportions of organic stabilizer suilice to maintain an admixture thereof with the heated chlorinated may be prolonged by the presence of marble or limestone in the apparatus, as explained above, and may be extended indefinitely by repeated timely additions of the stabilizing agent.

The. boiling points of volatile aliphatic chlorinated solvents hereinbefore mentioned are as follows:

Accordingly, I have limited certain of my claims to aliphatic (or other) chlorinated solvents boiling under substantially 150 0., together with alkaloid stabilizers.

Having thus described my invention, I claim:

1. An improved process of treating greasy objects with hot volatile organic chlorinated grease solvents that decompose when exposed in the hot vapor state to the atmosphere or to moisture. with generation of chlorine acid, and of preventing the decomposition of the solvent, notwithstanding such exposure; which process comprises heating and vaporizing the organic chlorinated solvent that is exposed to the atmosphere or to moisture in the presence of stabilizing vegetable alkaloid that is compatible with the moist chlorinated solvent; and treating the objects with the solvent thus stabilized, while maintaining the admixture of alkaloid with the chlorinated solvent during the exposure of the solvent to the atmosphere or to moisture.

2. An improved process of treating greasy objects with hot volatile organic chlorinated grease solvents that decompose when exposed in the hot vapor state to the atmosphere or to moisture, and of preventing corrosion oi metal parts, whether of the apparatus used or the objects being treated, that come in contact with such hot liquid or vaporous solvent, notwithstanding the exposure of the solvent; which process comprises heating and vaporizing the organic chlorinated solvent that is exposed to the atmosphere or to moisture in the presence of stabilizing vegetable alkaloid that is chlorinatable and is compatible with the moist chlorinated solvent; and treating the objects with the solvent thus stabilized, while maintaining the admixture of alkaloid with thechlorinated solvent during the exposure of the metal parts to the solvent and of the solvent to the atmosphere or to moisture.

3. An improved process of treating greasy objects with hot volatile organic chlorinated grease solvents that decompose when exposed in the hot vapor state to the atmosphere or to moisture, and of preventing corrosion of metal parts,

whether of the apparatus used or the obiects being treated, that come in contact with such hot liquid or vaporous solvent, notwithstanding the exposure of the solvent; which process comprises heating and vaporizing the organic chlorinated solvent that is exposed to the atmosphere or to moisture in the presence of corrosionpreventing vegetable alkaloid that is soluble in -and compatible with the moist chlorinated solvent, and imparts an alkaline reaction thereto; and treating the objects with the solvent thus stabilized, while maintaining the admixture of alkaloid with the chlorinated solvent during the exposure of the metal parts to the solvent and Of the solvent to the atmosphere or to moisture. 7

4. An improved process of treating greasy objects with hot volatile organic chlorinated grease solvents that decompose when exposed in the hot vapor state to the atmosphere or to moisture, with generation of chlorine acid,'and of preventing the decomposition of the solvent, notwithstanding such exposure; which process comprises heating and vaporizing the organic chlorinated solvent that is exposed to the atmosphere or to moisture in the presence of stabilizing alkaloid of the class consisting of cafieine and quinine, that is soluble in and compatible with the moist chlorinated solvent; and treating the objects with the solvent thus stabilized, while maintaining the admixture of alkaloid with the chlorinated solvent during the exposure of the solvent to the atmosphere or to moisture.

5. An improved process of treating greasy objects with hot volatile organic chlorinated grease solvents that decompose when exposed in the hot vapor state to the atmosphere or to moisture, with generation of chlorine acid, and of preventing the decomposition of the solvent, notwithstanding such exposure; which process comprises heating and vaporizing the organic chlorinated solvent that is exposed to the atmosphere or to moisture in the presence of the alkaloid caffeine as a stabilizer; and treating the work with the solvent thus stabilized, while maintaining the admixture of alkaloid with the chlorinated solvent during the exposure of the solvent to the atmosphere or to moisture.

6. An oil and grease solvent composition, stabilized and adapted for cleaning or grease-solvent use while hot under atmospheric exposure or with moisture, and comprising volatile ch10- rinated hydrocarbon grease solvent boiling under substantially 150 C., in combination with a compatible stabilizing vegetable alkaloid present in sufficient proportion to impart an alkaline reaction to the composition, and to stabilize the solvent against decomposition when boiled.

7. An oil and grease solvent composition, stabilized and adapted for cleaning or grease-solvent use while hot under atmospheric exposure or with moisture, and comprising volatile chlorinated. aliphatic hydrocarbon grease solvent boiling under substantially 150 C., in combination with a fraction of a percent of compatible stabilizing vegetable alkaloid that is soluble in the moist chlorinated solvent, and is sufficient in amount to impart an alkaline reaction to the composition, and to stabilize the solvent against decomposition when boiled,

8. An oil and grease solvent composition, stabilized and adapted for cleaning or grease-solvent use while hot under atmospheric exposure or with moisture, and comprising volatile chlorinated hydrocarbon grease solvent boiling under substantially 150 C., in combination with compatible stabilizing vegetable alkaloid, of the class consisting of caffeine and quinine, present in sufficient proportion to impart an alkaline reaction to the composition, and to stabilize the solvent against decomposition when boiled.

9. An oil and grease solvent composition, stabilized and adapted for cleaning or grease-solvent use while hot under atmospheric exposure or with moisture, and comprising trichlorethylene in combination with a fraction of a percent of compatible stabilizing vegetable alkaloid sufiicient to impart an alkaline reaction to the composition, and to stabilize the trichlorethylene against decomposition when boiled.

10. An oil and grease solvent composition, stabilized and adapted for cleaning or grease-solvent use while hot under atmospheric exposure or with moisture, and comprising trichlorethylene in combination with a fraction of a percent of cafieine suificient to impart an alkaline reaction to the composition, and to stabilize the trichlorethylene against decomposition when boiled.

CLARENCE F. DINLEY. 

